The Democratic and Republican parties of Oregon are urging nonaffiliated voters to sign up for a party or risk being left out of a big share of the May 15 primary.

It’s a great idea. The best part is that nonaffiliated voters can switch into a party, have an impact in the primary election and then switch back to being nonaffiliated.

But they have to move fast. They have to sign up for a party — at least temporarily — before April 24.

Oregon has a closed primary system. So only registered Democrats can vote in the Democratic primary. And only registered Republicans can vote in the Republican primary.

Those parties could open up their primaries to all registered voters — as the Independent Party has done. But the Democrats and Republicans haven’t done that for this primary.

It’s a big deal because so many Oregonians are nonaffiliated.

Nonaffiliated voters have been the fastest growing segment of registered voters. As of February, there were more nonaffiliated registered Oregonians than Republicans. There were 956,149 Democrats, 820,370 nonaffiliated and 696,525 Republicans. That’s out of 2.6 million registered voters.

How is it good that 820,000 people are cut out of this stage of the election process? Not being able to vote in the primary cuts them out of a vital piece of the electoral process — choosing the major candidates who will appear on the November ballot. The nonaffiliated are effectively disenfranchised.

We should note that nonaffiliated voters will still get a ballot and will be able to vote on things, such as local tax measures — if any — the proposed changes to Bend city government and other local matters that are not party primaries. We’d love to see the Democratic and Republican parties follow the lead of the Independent Party and open up their primaries. That’s not going to happen, yet. But nonaffiliated voters who don’t want to be cut out can go to sos.oregon.gov/voting/Pages/registration and make the quick switch. It takes about a minute.

Whatever you decide to do, please take advantage of the privilege of being able to vote to choose your government.